Soft, low lint, through air dried tissue and method of forming the same

ABSTRACT

A multi-ply through air dried structured tissue having a bulk softness of less than 10 TS7 and a lint value of 5.0 or less. Each ply of the tissue has a first exterior layer that includes a wet end temporary wet strength additive in an amount of approximately 0.25 kg/ton and a wet end dry strength additive in an amount of approximately 0.25 kg/ton, an interior layer that includes a first wet end additive comprising an ionic surfactant, and a second wet end additive comprising a non-ionic surfactant, and a second exterior layer.

RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.17/163,922, filed Feb. 1, 2021 and entitled SOFT, LOW LINT, THROUGH AIRDRIED TISSUE AND METHOD OF FORMING THE SAME, which in turn is acontinuation of U.S. Pat. Application Serial No. 16/598,028, filed Oct.10, 2019 and entitled SOFT, LOW LINT, THROUGH AIR DRIED TISSUE ANDMETHOD OF FORMING THE SAME, which in turn is a continuation of U.S. Pat.Application Serial No. 16/378,790, filed Apr. 9, 2019 and entitled SOFT,LOW LINT, THROUGH AIR DRIED TISSUE AND METHOD OF FORMING THE SAME, nowU.S. Pat. No. 10,844,548, which in turn is a continuation of U.S. Pat.Application Serial No. 15/499,457, filed Apr. 27, 2017 and entitledSOFT, LOW LINT, THROUGH AIR DRIED TISSUE AND METHOD OF FORMING THE SAME,now U.S. Patent No. 10,301,779, which in turn claims priority under 35U.S.C. § 119(e) to U.S. Provisional Patent Application Serial No.62/328,350, entitled Soft, Low Lint, Through Air Dried Tissue and Methodof Forming the Same and filed on Apr. 27, 2016, the contents of whichare incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention is directed to tissue, and in particular to amultilayer tissue including wet end additives.

BACKGROUND

Across the globe there is great demand for disposable paper productssuch as sanitary tissue and facial tissue. In the North American market,the demand is increasing for higher quality products offered at areasonable price point. The quality attributes most important forconsumers of disposable sanitary tissue is softness and strength.Another attribute desired by consumers is low lint, which refers to theamount of fibers that are liberated from the product during use.

Fabric crepe is the process of using speed differential between aforming and structured fabric to facilitate filling the valleys of thestructured fabric with fiber, and folding the web in the Z-direction tocreate thickness and influence surface topography. Conventional crepingis the use of a doctor blade to remove a web that is adhered to a steamheated cylinder (yankee dryer), coated with an adhesive chemistry, inconjunction with speed differential between the yankee dryer and reeldrum to fold the web in the Z-direction to create thickness, drape, andto influence the surface topography of the web. The process ofcalendering, pressing the web between cylinders, will also affectsurface topography. The surface topography can also be influenced by thecoarseness and stiffness of the fibers used in the web, degree of fiberrefining, as well as embossing in the converting process. Added chemicalsofteners and lotions can also affect the perception of smoothness bycreating a lubricious surface coating that reduces friction between theweb and the skin of the consumer.

Lint, or the amount of fibers liberated from the web during use can beaffected by many things such as the overall strength of the web, theincorporation of natural or synthetic binders (especially in outersurface of the web which is exposed to direct contact with theconsumer), the smoothness of the outer surface of the web, the size ofthe fibers or stratification of the fibers throughout the web, and thegeometry of the creping doctor used to crepe the sheet from the yankeedryer.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a tissue manufacturingmethod that uses through air drying to produce a tissue with exceptionalsoftness and low lint.

A multi-layer through air dried tissue according to an exemplaryembodiment of the present invention comprises a first exterior layer, aninterior layer and a second exterior layer. The interior layer includesa first wet end additive comprising an ionic surfactant and a second wetend additive comprising a non-ionic surfactant.

A multi-layer through air dried tissue according to another exemplaryembodiment of the present invention comprises a first exterior layercomprised substantially of hardwood fibers, an interior layer comprisedsubstantially of softwood fibers, and a second exterior layer comprisedsubstantially of hardwood fibers. The interior layer includes a firstwet end additive comprising an ionic surfactant and a second wet endadditive comprising a non-ionic surfactant.

In at least one exemplary embodiment, the first exterior layer furthercomprises a wet end temporary wet strength additive.

In at least one exemplary embodiment, the first exterior layer furthercomprises a wet end dry strength additive.

In at least one exemplary embodiment, the second exterior layer furthercomprises a wet end dry strength additive.

In at least one exemplary embodiment, the second wet end additivecomprises an ethoxylated vegetable oil.

In at least one exemplary embodiment, the second wet end additivecomprises a combination of ethoxylated vegetable oils.

In at least one exemplary embodiment, the ratio by weight of the secondwet end additive to the first wet end additive in the tissue is at leasteight to one.

In at least one exemplary embodiment, the ratio by weight of the secondwet end additive to the first wet end additive in the first interiorlayer is at most ninety to one.

In at least one exemplary embodiment, the ionic surfactant comprises adebonder.

In at least one exemplary embodiment, a 2-ply laminate of the tissue webhas a softness (hand feel) of at least 91 HF.

In at least one exemplary embodiment, a 2-ply laminate of the tissue webhas a bulk softness of less than 10 TS7.

In at least one exemplary embodiment, the wet end temporary wet strengthadditive comprises glyoxalated polyacrylamide.

In at least one exemplary embodiment, the wet end dry strength additivecomprises amphoteric starch.

In at least one exemplary embodiment, the first exterior layer furthercomprises a dry strength additive.

In at least one exemplary embodiment, the first and second exteriorlayers are substantially free of any surface deposited softener agentsor lotions.

In at least one exemplary embodiment, at least one of the first orsecond exterior layers comprises a surface deposited softener agent orlotion.

In at least one exemplary embodiment, the non-ionic surfactant has ahydrophilic-lipophilic balance of less than 10, and preferably less than8.5.

In at least one exemplary embodiment, the first exterior layer iscomprised of at least 20% by weight of softwood fibers.

In at least one exemplary embodiment, the interior layer is comprised ofat least 75% by weight of softwood fibers.

A structured tissue according to an exemplary embodiment of the presentinvention comprises: a laminate of at least two plies of a multi-layerthrough air dried tissue, the structured tissue having a bulk softnessof less than 10 TS7 and a lint value of 5.0 or less.

In at least one exemplary embodiment, the structured tissue has asoftness value of 91.0 HF or greater.

Other features and advantages of embodiments of the invention willbecome readily apparent from the following detailed description, theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described withreferences to the accompanying figures, wherein:

FIG. 1 is a schematic diagram of a three layer tissue in accordance withan exemplary embodiment of the present invention;

FIG. 2 is a block diagram of a system for manufacturing a single ply ofthe multi-ply tissue according to an exemplary embodiment of the presentinvention;

FIG. 3 is a block diagram of a system for manufacturing a multi-plytissue from the single plies of tissue according to an exemplaryembodiment of the present invention;

FIG. 4 illustrates a conventional creping blade;

FIG. 5 illustrates an example of a creping blade according to anexemplary embodiment of the present invention; and

FIG. 6 illustrates an example of a creping blade according to anotherexemplary embodiment of the present invention.

DETAILED DESCRIPTION

Manufacturers of disposable paper products have long recognized a strongconsumer demand for tissues, such as bath tissues and facial tissues,that are both soft and strong. Softness refers to the tactile sensationor “hand feel” that a consumer perceives when using the tissue. Thestrength is the ability of a paper web to retain its physical integrityduring use. In making a tissue that is both soft and strong, there istypically a tradeoff between strength and softness. For example,manufacturers may make a tissue softer by adding more hardwood, whichtends to be softer due to shorter fibers in the wood, but this reducessheet strength.

While consumers tend to prefer the softer tissues, consumers aresensitive to the lint that is commonly liberated (released) from thesoft tissues during use and left behind as residue on the user’s skin orclothing. Conventional techniques used to reduce lint also make thetissue considerably less soft. For example, adding dry strength additiveor temporary wet strength additive to the tissue or increasing theamount of long fiber softwood used to make the tissue, reduces lint butcauses the tissue to be less soft. For this reason, it is desirable tofurther reduce the amount of lint released from a soft and strongtissue.

The reduction in lint is achieved in the present invention bycontrolling the surface fiber bonding to prevent the surface fibers frombreaking away when the tissue is used. As described in further detailherein, the surface fiber bonding is controlled, for example, bysupplying additives at the multi-layer headbox or by polymer/fibermigration during sheet formation. The resulting tissue satisfiesconsumers who prefer a soft but strong tissue with very low levels oflint.

The present invention is directed to a soft structured tissue made witha combination of a wet end added ionic surfactant and a wet end addednonionic surfactant. The term “structured tissue” may refer to anytissue product made using a structuring fabric to develop a pattern inthe tissue web in a papermaking process, such as, for example, TAD,UCTAD, ATMOS, NTT, or ETAD. The tissue may be made up of a number oflayers, including exterior layers and an interior layer. In at least oneexemplary embodiment, pulp mixes for each tissue layer are preparedindividually.

FIG. 1 shows a three layer tissue, generally designated by referencenumber 1, according to an exemplary embodiment of the present invention.The general structure and manufacturing process of the tissue 1 are asdescribed in U.S. Pat. No. 8,968,517 (assigned to applicant), thecontents of which are incorporated herein by reference in theirentirety. The tissue 1 has external layers 2 and 4 as well as aninternal, core layer 3. External layer 2 is composed primarily ofhardwood fibers 20 whereas external layer 4 and core layer 3 arecomposed of a combination of hardwood fibers 20 and softwood fibers 21.The internal core layer 3 includes an ionic surfactant functioning as adebonder 5 and a non-ionic surfactant functioning as a softener 6. Asexplained in further detail below, external layers 2 and 4 also includenon-ionic surfactant that migrated from the internal core layer 3 duringformation of the tissue 1. External layer 2 further includes a drystrength additive 7. External layer 4 further includes both a drystrength additive 7 and a temporary wet strength additive 8.

Pulp mixes for exterior layers of the tissue are prepared with a blendof primarily hardwood fibers. For example, the pulp mix for at least oneexterior layer is a blend containing about 70 percent or greaterhardwood fibers relative to the total percentage of fibers that make upthe blend. As a further example, the pulp mix for at least one exteriorlayer is a blend containing about 80 percent hardwood fibers relative tothe total percentage of fibers that make up the blend.

Pulp mixes for the interior layer of the tissue are prepared with ablend of primarily softwood fibers. For example, the pulp mix for theinterior layer is a blend containing about 70 percent or greatersoftwood fibers relative to the total percentage of fibers that make upthe blend. As a further example, the pulp mix for the interior layer isa blend containing about 90-100 percent softwood fibers relative to thetotal percentage of fibers that make up the blend.

As known in the art, pulp mixes are subjected to a dilution stage inwhich water is added to the mixes so as to form a slurry. After thedilution stage but prior to reaching the headbox, each of the pulp mixesare dewatered to obtain a thick stock of about 95% water. In anexemplary embodiment of the invention, wet end additives are introducedinto the thick stock pulp mixes of at least the interior layer. In anexemplary embodiment, a non-ionic surfactant and an ionic surfactant areadded to the pulp mix for the interior layer. Suitable non-ionicsurfactants have a hydrophilic-lipophilic balance of less than 10, andpreferably less than or equal to 8.5. An exemplary non-ionic surfactantis an ethoxylated vegetable oil or a combination of two or moreethoxylated vegetable oils. Other exemplary non-ionic surfactantsinclude ethylene oxide, propylene oxide adducts of fatty alcohols,alkylglycoside esters, and alkylethoxylated esters.

Suitable ionic surfactants include but are not limited to quaternaryamines and cationic phospholipids. An exemplary ionic surfactant is1,2-di(heptadecyl)-3-methyl-4,5-dihydroimidazol-3-ium methyl sulfate.Other exemplary ionic surfactants include(2-hydroxyethyl)methylbis[2-[(1-oxooctadecyl)oxy]ethyl]ammonium methylsulfate, fatty dialkyl amine quaternary salts, mono fatty alkyl tertiaryamine salts, unsaturated fatty alkyl amine salts, linear alkylsulfonates, alkyl-benzene sulfonates andtrimethyl-3-[(1-oxooctadecyl)amino]propylammonium methyl sulfate.

In an exemplary embodiment, the ionic surfactant may function as adebonder while the non-ionic surfactant functions as a softener.Typically, the debonder operates by breaking bonds between fibers toprovide flexibility, however an unwanted side effect is that the overallstrength of the tissue can be reduced by excessive exposure to debonder.Typical debonders are quaternary amine compounds such as trimethylcocoammonium chloride, trymethyloleylammonium chloride,dimethyldi(hydrogenated-tallow)ammonium chloride andtrimethylstearylammonium chloride.

After being added to the interior layer, the non-ionic surfactant(functioning as a softener) migrates through the other layers of thetissue while the ionic surfactant (functioning as a debonder) staysrelatively fixed within the interior layer. Since the debonder remainssubstantially within the interior layer of the tissue, softer hardwoodfibers (that may have lacked sufficient tensile strength if treated witha debonder) can be used for the exterior layers. Further, because onlythe interior of the tissue is treated, less debonder is required ascompared to when the whole tissue is treated with debonder.

In an exemplary embodiment, the ratio of ionic surfactant to non-ionicsurfactant added to the pulp mix for the interior layer of the tissue isbetween 1:4 and 1:90 parts by weight and preferably about 1:8 parts byweight. In particular, when the ionic surfactant is a quaternary aminedebonder, reducing the concentration relative to the amount of non-ionicsurfactant can lead to an improved tissue. Excess debonder, particularlywhen introduced as a wet end additive, can weaken the tissue, while aninsufficient amount of debonder may not provide the tissue withsufficient flexibility. Because of the migration of the non-ionicsurfactant to the exterior layers of the tissue, the ratio of ionicsurfactant to non-ionic surfactant in the core layer may besignificantly lower in the actual tissue compared to the pulp mix.

In an exemplary embodiment, a dry strength additive is added to thethick stock mix for at least one of the exterior layers. The drystrength additive may be, for example, amphoteric starch, added in arange of about 1 to 40 kg/ton. In another exemplary embodiment, a wetstrength additive is added to the thick stock mix for at least one ofthe exterior layers. The wet strength additive may be, for example,glyoxalated polyacrylamide, commonly known as GPAM, added in a range ofabout 0.25 to 5 kg/ton. In a further exemplary embodiment, both a drystrength additive, preferably amphoteric starch and a wet strengthadditive, preferably GPAM are added to one of the exterior layers.Without being bound by theory, it is believed that the combination ofboth amphoteric starch and GPAM in a single layer when added as wet endadditives provides a synergistic effect with regard to strength of thefinished tissue to reduce linting. Other exemplary temporarywet-strength agents include aldehyde functionalized cationic starch,aldehyde functionalized polyacrylamides, acrolein co-polymers andcis-hydroxyl polysachharide (guar gum and locust bean gum) used incombination with any of the above mentioned compounds.

In addition to amphoteric starch, suitable dry strength additives mayinclude but are not limited to glyoxalated polyacrylamide, cationicstarch, carboxy methyl cellulose, guar gum, locust bean gum, cationicpolyacrylamide, polyvinyl alcohol, anionic polyacrylamide or acombination thereof.

FIG. 2 is a block diagram of a system for manufacturing tissue,generally designated by reference number 100, according to an exemplaryembodiment of the present invention. The system 100 includes an firstexterior layer fan pump 102, a core layer fan pump 104, a secondexterior layer fan pump 106, a headbox 108, a forming section 110, adrying section 112 and a calendar section 114. The first and secondexterior layer fan pumps 102, 106 deliver the pulp mixes of the firstand second external layers 2, 4 to the headbox 108, and the core layerfan pump 104 delivers the pulp mix of the core layer 3 to the headbox108. As is known in the art, the headbox delivers a wet web of pulp ontoa forming wire within the forming section 110. The wet web is laid onthe forming wire with the core layer 3 disposed between the first andsecond external layers 2, 4.

After formation in the forming section 110, the partially dewatered webis transferred to the drying section 112, Within the drying the section112, the tissue of the present invention may be dried using conventionalthrough air drying processes. In an exemplary embodiment, the tissue ofthe present invention is dried to a humidity of about 7 to 20% using athrough air drier manufactured by Metso Corporation, of Helsinki,Finland. In another exemplary embodiment of the invention, two or morethrough air drying stages are used in series. Without being bound bytheory, it is believed that the use of multiple drying stages improvesuniformity in the tissue, thus reducing tears.

In an exemplary embodiment, the tissue of the present invention ispatterned during the through air drying process. Such patterning can beachieved through the use of a TAD fabric, such as a G-weave (Prolux 003)or M-weave (Prolux 005) TAD fabric.

After the through air drying stage, the tissue of the present inventionmay be further dried in a second phase using a Yankee drying drum. In anexemplary embodiment, a creping adhesive is applied to the drum prior tothe tissue contacting the drum. The tissue adheres to the drum and isremoved using a wear resistant coated creping blade with a creping shelfof 0.5 mm or less. The creping doctor set up angle is preferably 10 to35 degrees, while the blade bevel is preferably 55 to 80 degrees.

To further illustrate the creping process, FIG. 4 shows a conventionalcreping blade application wherein a creping blade 401 is pressed againsta steam heated drum 403 in order to crepe a tissue web 402. The blade401 may be provided with a wear resistant material 404 at the blade tip.The available distance on the blade available for contact with the paperweb is called the distance of the creping shelf or creping shelfdistance. In FIG. 4 showing a conventional creping blade application,the distance of the creping shelf 415 is the same as the thickness ofthe creping blade 414.

In the creping process used in accordance with an exemplary embodimentof the present invention, as shown in FIG. 5 , the distance of thecreping shelf 515 has been reduced to 0.5 mm or less by beveling thenon-contacting face of the blade 512. The angle of the bevel b isselected to obtain the desired creping shelf distance. It has beendiscovered that the distance of the creping shelf 515 can influence theweb properties including tensile, bulk, and lint since the distance ofthe creping shelf directly influences the contact time between the blade512 and web 502 and thus the forces imparted to the web by the blade.For example, it has been observed that as the creping shelf distance isdecreased, there is a less tensile destruction at the blade and also ahigher bulk generation.

In another exemplary embodiment, as shown in FIG. 6 , a 25 degree bladeset up angle c, which is measured from a normal line at the contactpoint between the blade tip and the drum to the face of the crepingblade 605, a wear resistant coated tip blade with an 80 degree bladebevel d, and a 0.5 mm creping shelf distance 615 is utilized.

The wear resistant material is suitably a ceramic material, a cermetmaterial, or a carbide material. For example, the wear resistantmaterial may be selected from metal oxides, ceramic materials,silicates, carbides, borides, nitrides, and mixtures thereof. Particularexamples of suitable wear resistant materials are alumina, chromia,zirconia, tungsten carbide, chromium carbide, zirconium carbide,tantalum carbide, titanium carbide, and mixtures thereof. Thewear-resistant material is applied by thermal spraying, physical vapordeposition, or chemical vapor deposition.

The tissue may then be calendered in a subsequent stage within thecalendar section 114. According to an exemplary embodiment, calendaringmay be accomplished using a number of calendar rolls (not shown) thatdeliver a calendering pressure in the range of 0-100 pounds per linearinch (PLI). In general, increased calendering pressure is associatedwith reduced caliper and a smoother tissue surface.

According to an exemplary embodiment of the invention, a ceramic coatedcreping blade is used to remove the tissue from the Yankee drying drum.Ceramic coated creping blades result in reduced adhesive build up andaid in achieving higher run speeds. Without being bound by theory, it isbelieved that the ceramic coating of the creping blades provides a lessadhesive surface than metal creping blades and is more resistant to edgewear that can lead to localized spots of adhesive accumulation. Theceramic creping blades allow for a greater amount of creping adhesive tobe used which in turn provides improved sheet integrity and faster runspeeds.

In addition to the use of wet end additives, the tissue of the presentinvention may also be treated with topical or surface depositedadditives. Examples of surface deposited additives include softeners forincreasing fiber softness and skin lotions. Examples of topicalsofteners include but are not limited to quaternary ammonium compounds,including, but not limited to, the dialkyldimethylammonium salts (e.g.ditallowdimethylammonium chloride, ditallowdimethylammonium methylsulfate, di(hydrogenated tallow)dimethyl ammonium chloride, etc.).Another class of chemical softening agents include the well-knownorgano-reactive polydimethyl siloxane ingredients, including aminofunctional polydimethyl siloxane. zinc stearate, aluminum stearate,sodium stearate, calcium stearate, magnesium stearate, spermaceti, andsteryl oil.

After the tissue basesheet is produced a laminate, composed of twowebs/plies are laminated together in a face-to face relationship usingan aqueous adhesive. The adhesives used to laminate the plies ofabsorbent structure can be water soluble of the group consisting ofpolyvinyl alcohol, polyvinyl acetate, starch based or mixtures thereof.The mixture is comprised of 1% to 10% by weight of the adhesives.Additionally; the mixture can contain up 10% by weight of a watersoluble cationic resin selected from the group consisting ofpolyamide-epichlorohydrin resins, glyoxalated polyacrylamide resins,polyethyleneimine resins, polyethylenimine resins, or mixtures thereof.The remainder of the mixture is composed of water. This mixture isheated and maintained to a temperature between 90 deg F to 150 deg F,preferably to 120 F.

The adhesive is heated and maintained at temperature utilizing aninsulated stainless steel tank with heating elements uniformlydistributed throughout the interior heating surface. The large amount ofsurface area heated provides uniform heating controlled by an adjustablethermostat. The tank is designed with an agitator that to ensure propermixing and heat transfer.

The adhesive is applied using an applicator roll, aligned in an axiallyparallel arrangement with one of the two embossing rolls forming a niptherewith, such that the adhesive applicator roll is upstream of the nipformed between the two embossing rolls. The adhesive applicator rolltransfers adhesive to the embossed webs on the embossing roll at thecrests of the embossing knobs. The crests of the embossing knobstypically do not touch the perimeter of the opposing roll at the nipformed therebetween necessitating the addition of a marrying roll toapply pressure for lamination. The marrying roll forms a nip with thesame embossing roll forming the nip with the adhesive applicator roll,downstream of the nip formed between the two embossing rolls.

According to an exemplary embodiment of the invention, the paper web onthe converting lines may be treated with corona discharge before theembossing section. This treatment may be applied to the top ply and/orbottom ply. Nano cellulose fibers (NCF), nano crystalline cellulose(NCC), micro-fibrillated cellulose (MCF) and other shaped natural andsynthetic fibers may be blown on to the paper web using a blower systemimmediately after corona treatment. This enables the nano-fibers toadsorb on to the paper web through electrostatic interactions

As discussed, according to an exemplary embodiment of the invention, adebonder is added to at least the interior layer as a wet end additive.The debonder provides flexibility to the finished tissue product.However, the debonder also reduces the strength of the tissue web, whichat times may result in sheet breaks during the manufacturing process.The relative softness of the tissue web results in inefficiencies in therewind process that must be performed in order to correct a sheet break.Accordingly, as shown in FIG. 2 , in an exemplary embodiment of thepresent invention, a switching valve 120 is used to control delivery ofthe debonder as a wet-end additive to the interior layer. In particular,when a sheet break is detected using, for example, conventional sheetbreak detection sensors, the switching valve 120 may be controlled toprevent further delivery of the debonder. This results in lessflexibility and increased strength at the portion of the tissue web tobe rewound, thereby allowing for a more efficient rewind process. Oncethe rewind process is completed, the switching valve may be opened tocontinue delivery of the debonder.

In addition to the use of a sheet break detection sensor, the switchingvalve 120 may also be controlled during turn up, the process whereby thetissue web is one transferred from on roll to another. The turn upprocess can result in higher stresses on the tissue web that normaloperation, thus increasing the chance of sheet breaks. The switchingvalve 120 is turned off prior to turn up, thus increasing the strengthof the tissue web. After the tissue web has begun winding on a new roll,the switching valve 120 is turned on again. The resulting roll ofbasesheet material thus has a section of higher strength tissue web atthe center of the roll and may have a section of higher strength tissueon the outside of the roll. During finishing, the exterior section ofhigher strength tissue is removed and recycled. The interior section ofhigher strength tissue is not used to make a finished tissue. Thus, onlythe portion of the roll of basesheet tissue containing debonder is usedto make finished tissue.

The below discussed values for basis weights, ball burst, MD and CDstretch and tensile strength, caliper, lint and softness of theinventive tissue were determined using the following test procedures:

Softness Testing

Softness of a 2-ply tissue web was determined using a Tissue SoftnessAnalyzer (TSA), available from EMTEC Electronic GmbH of Leipzig,Germany. The TSA comprises a rotor with vertical blades which rotate onthe test piece to apply a defined contact pressure. Contact between thevertical blades and the test piece creates vibrations which are sensedby a vibration sensor. The sensor then transmits a signal to a PC forprocessing and display. The frequency analysis in the range ofapproximately 200 to 1000 Hz represents the surface smoothness ortexture of the test piece and is referred to as the TS750 value. Afurther peak in the frequency range between 6 and 7 kHz represents thebulk softness of the test piece and is referred to as the TS7 value.Both TS7 and TS750 values are expressed as dB V² rms. The stiffness ofthe sample is also calculated as the device measures deformation of thesample under a defined load. The stiffness value (D) is expressed asmm/N. The device also calculates a Hand Feel (HF) number with the valuecorresponding to a softness as perceived when someone touches a tissuesample by hand (the higher the HF number, the higher the softness). TheHF number is a combination of the TS750, TS7, and stiffness of thesample measured by the TSA and calculated using an algorithm which alsorequires the caliper and basis weight of the sample. Differentalgorithms can be selected for different facial, toilet, and towel paperproducts. Before testing, a calibration check should be performed using“TSA Leaflet Collection No. 9” available from EMTECH dated 2016-05-10.If the calibration check demonstrates a calibration is necessary, “TSALeaflet Collection No. 10” is followed for the calibration procedureavailable from EMTECH dated 2015-09-09.

A punch was used to cut out five 100 cm² round samples from the web. Oneof the samples was loaded into the TSA, clamped into place (outwardfacing or embossed ply facing upward), and the TPII algorithm wasselected from the list of available softness testing algorithmsdisplayed by the TSA. After inputting parameters for the sample(including caliper and basis weight), the TSA measurement program wasrun. The test process was repeated for the remaining samples and theresults for all the samples were averaged and the average HF numberrecorded.

Ball Burst Testing

Ball Burst of a 2-ply tissue web was determined using a Tissue SoftnessAnalyzer (TSA), available from EMTECH Electronic GmbH of Leipzig,Germany using a ball burst head and holder. A punch was used to cut outfive 100 cm² round samples from the web. One of the samples was loadedinto the TSA, with the embossed surface facing down, over the holder andheld into place using the ring. The ball burst algorithm was selectedfrom the list of available softness testing algorithms displayed by theTSA. The ball burst head was then pushed by the EMTECH through thesample until the web ruptured and the grams force required for therupture to occur was calculated. The test process was repeated for theremaining samples and the results for all the samples were averaged.

Stretch & MD, CD, and Wet CD Tensile Strength Testing

An Instron 3343 tensile tester, manufactured by Instron of Norwood, MA,USA, with a 100N load cell and 25.4 mm rubber coated jaw faces was usedfor tensile strength measurement. Prior to measurement, the Instron 3343tensile tester was calibrated. After calibration, 8 strips of 2-plyproduct, each one inch by four inches, were provided as samples for eachtest. When testing MD, the strips were cut in the MD direction and inthe CD direction when testing CD. One of the sample strips was placed inbetween the upper jaw faces and clamp, and then between the lower jawfaces and clamp with a gap of 2 inches between the clamps. A test wasrun on the sample strip to obtain tensile and stretch. The testprocedure was repeated until all the samples were tested. The valuesobtained for the eight sample strips were averaged to determine thetensile strength of the tissue. When testing CD wet tensile, the stripswere placed in an oven at 105 deg Celsius for 5 minutes and saturatedwith 75 microliters of deionized water immediately prior to pulling thesample.

Lint Testing

The amount of lint generated from a tissue product was determined with aSutherland Rub Tester. This tester uses a motor to rub a weighted felt 5times over the stationary tissue. The Hunter Color L value is measuredbefore and after the rub test. The difference between these two HunterColor L values is calculated as lint.

Lint Testing - Sample Preparation

Prior to the lint rub testing, the paper samples to be tested should beconditioned according to Tappi Method #T4020M-88. Here, samples arepreconditioned for 24 hours at a relative humidity level of 10 to 35%and within a temperature range of 22° to 40° C. After thispreconditioning step, samples should be conditioned for 24 hours at arelative humidity of 48 to 52% and within a temperature range of 22° to24° C. This rub testing should also take place within the confines ofthe constant temperature and humidity room.

The Sutherland Rub Tester may be obtained from Testing Machines, Inc.(Amityville, N.Y. 11701). The tissue is first prepared by removing anddiscarding any product which might have been abraded in handling, e.g.on the outside of the roll. For multi-ply finished product, threesections with each containing two sheets of multi-ply product areremoved and set on the bench-top. For single-ply product, six sectionswith each containing two sheets of single-ply product are removed andset on the bench-top. Each sample is then folded in half such that thecrease is running along the cross direction (CD) of the tissue sample.For the multi-ply product, make sure one of the sides facing out is thesame side facing out after the sample is folded. In other words, do nottear the plies apart from one another and rub test the sides facing oneanother on the inside of the product. For the single-ply product, makeup 3 samples with the off-Yankee side out and 3 with the Yankee sideout. Keep track of which samples are Yankee side out and which areoff-Yankee side out.

Obtain a 30″×40″ piece of Crescent #300 cardboard from Cordage Inc. (800E. Ross Road, Cincinnati, Ohio, 45217). Using a paper cutter, cut outsix pieces of cardboard of dimensions of 2.5″×6″. Puncture two holesinto each of the six cards by forcing the cardboard onto the hold downpins of the Sutherland Rub tester.

If working with single-ply finished product, center and carefully placeeach of the 2.5″×6″ cardboard pieces on top of the six previously foldedsamples. Make sure the 6″ dimension of the cardboard is running parallelto the machine direction (MD) of each of the tissue samples. If workingwith multi-ply finished product, only three pieces of the 2.5″×6″cardboard will be required. Center and carefully place each of thecardboard pieces on top of the three previously folded samples. Onceagain, make sure the 6″ dimension of the cardboard is running parallelto the machine direction (MD) of each of the tissue samples.

Fold one edge of the exposed portion of tissue sample onto the back ofthe cardboard. Secure this edge to the cardboard with adhesive tapeobtained from 3M Inc. (¾″ wide Scotch Brand, St. Paul, Minn.). Carefullygrasp the other over-hanging tissue edge and snugly fold it over ontothe back of the cardboard. While maintaining a snug fit of the paperonto the board, tape this second edge to the back of the cardboard.Repeat this procedure for each sample.

Turn over each sample and tape the cross direction edge of the tissuepaper to the cardboard. One half of the adhesive tape should contact thetissue paper while the other half is adhering to the cardboard. Repeatthis procedure for each of the samples. If the tissue sample breaks,tears, or becomes frayed at any time during the course of this samplepreparation procedure, discard and make up a new sample with a newtissue sample strip.

If working with multi-ply converted product, there will now be 3 sampleson the cardboard. For single-ply finished product, there will now be 3off-Yankee side out samples on cardboard and 3 Yankee side out sampleson cardboard.

Lint Testing - Felt Preparation

Obtain a 30″×40″ piece of Crescent #300 cardboard from Cordage Inc. (800E. Ross Road, Cincinnati, Ohio, 45217). Using a paper cutter, cut outsix pieces of cardboard of dimensions of 2.25″×7.25″. Draw two linesparallel to the short dimension and down 1.125″ from the top and bottommost edges on the white side of the cardboard. Carefully score thelength of the line with a razor blade using a straight edge as a guide.Score it to a depth about half way through the thickness of the sheet.This scoring allows the cardboard/felt combination to fit tightly aroundthe weight of the Sutherland Rub tester. Draw an arrow running parallelto the long dimension of the cardboard on this scored side of thecardboard.

Cut the six pieces of black felt (F-55 or equivalent from New EnglandGasket, 550 Broad Street, Bristol, Conn. 06010) to the dimensions of2.25″×8.5″×0.0625. Place the felt on top of the unscored, green side ofthe cardboard such that the long edges of both the felt and cardboardare parallel and in alignment. Make sure the fluffy side of the felt isfacing up. Also allow about 0.5″ to overhang the top and bottom mostedges of the cardboard. Snuggly fold over both overhanging felt edgesonto the backside of the cardboard with Scotch brand tape. Prepare atotal of six of these felt/cardboard combinations.

For best reproducibility, all samples should be run with the same lot offelt. Obviously, there are occasions where a single lot of felt becomescompletely depleted. In those cases where a new lot of felt must beobtained, a correction factor should be determined for the new lot offelt. To determine the correction factor, obtain a representative singletissue sample of interest, and enough felt to make up 24 cardboard/feltsamples for the new and old lots.

As described below and before any rubbing has taken place, obtain HunterL readings for each of the 24 cardboard/felt samples of the new and oldlots of felt. Calculate the averages for both the 24 cardboard/feltsamples of the old lot and the 24 cardboard/felt samples of the new lot.

Next, rub test the 24 cardboard/felt boards of the new lot and the 24cardboard/felt boards of the old lot as described below. Make sure thesame tissue lot number is used for each of the 24 samples for the oldand new lots. In addition, sampling of the paper in the preparation ofthe cardboard/tissue samples must be done so the new lot of felt and theold lot of felt are exposed to as representative as possible of a tissuesample. For the case of 1-ply tissue product, discard any product whichmight have been damaged or abraded. Next, obtain 48 strips of tissueeach two usable units (also termed sheets) long. Place the first twousable unit strip on the far left of the lab bench and the last of the48 samples on the far right of the bench. Mark the sample to the farleft with the number “1” in a 1 cm by 1 cm area of the corner of thesample. Continue to mark the samples consecutively up to 48 such thatthe last sample to the far right is numbered 48.

Use the 24 odd numbered samples for the new felt and the 24 evennumbered samples for the old felt. Order the odd number samples fromlowest to highest. Order the even numbered samples from lowest tohighest. Now, mark the lowest number for each set with a letter “Y.”Mark the next highest number with the letter “O.” Continue marking thesamples in this alternating “Y”/“O” pattern. Use the “Y” samples foryankee side out lint analyses and the “O” samples for off-Yankee sidelint analyses. For 1-ply product, there are now a total of 24 samplesfor the new lot of felt and the old lot of felt. Of this 24, twelve arefor yankee side out lint analysis and 12 are for off-yankee side lintanalysis.

Rub and measure the Hunter Color L values for all 24 samples of the oldfelt as described below. Record the 12 yankee side Hunter Color L valuesfor the old felt. Average the 12 values. Record the 12 off-yankee sideHunter Color L values for the old felt. Average the 12 values. Subtractthe average initial un-rubbed Hunter Color L felt reading from theaverage Hunter Color L reading for the yankee side rubbed sambles. Thisis the delta average difference for the yankee side samples. Subtractthe average initial un-rubbed Hunter Color L felt reading from theaverage Hunter Color L reading for the off-yankee side rubbed sambles.This is the delta average difference for the off-yankee side samples.Calculate the sum of the delta average difference for the yankee-sideand the delta average difference for the off-yankee side and divide thissum by 2. This is the uncorrected lint value for the old felt. If thereis a current felt correction factor for the old felt, add it to theuncorrected lint value for the old felt. This value is the correctedLint Value for the old felt.

Rub and measure the Hunter Color L values for all 24 samples of the newfelt as described below. Record the 12 yankee side Hunter Color L valuesfor the new felt. Average the 12 values. Record the 12 off-yankee sideHunter Color L values for the new felt. Average the 12 values. Subtractthe average initial un-rubbed Hunter Color L felt reading from theaverage Hunter Color L reading for the yankee side rubbed sambles. Thisis the delta average difference for the yankee side samples. Subtractthe average initial un-rubbed Hunter Color L felt reading from theaverage Hunter Color L reading for the off-yankee side rubbed samples.This is the delta average difference for the off-yankee side samples.Calculate the sum of the delta average difference for the yankee-sideand the delta average difference for the off-yankee side and divide thissum by 2. This is the uncorrected lint value for the new felt.

Take the difference between the corrected Lint Value from the old feltand the uncorrected lint value for the new felt. This difference is thefelt correction factor for the new lot of felt.

Adding this felt correction factor to the uncorrected lint value for thenew felt should be identical to the corrected Lint Value for the oldfelt.

The same type procedure is applied to two-ply tissue product with 24samples run for the old felt and 24 run for the new felt. But, only theconsumer used outside layers of the plies are rub tested. As notedabove, make sure the samples are prepared such that a representativesample is obtained for the old and new felts.

Lint Testing - Care of 4 Pound Weight

The four pound weight has four square inches of effective contact areaproviding a contact pressure of one pound per square inch. Since thecontact pressure can be changed by alteration of the rubber pads mountedon the face of the weight, it is important to use only the rubber padssupplied by the manufacturer (Brown Inc., Mechanical ServicesDepartment, Kalamazoo, Mich.). These pads must be replaced if theybecome hard, abraded or chipped off.

When not in use, the weight must be positioned such that the pads arenot supporting the full weight of the weight. It is best to store theweight on its side.

Lint Testing - Rub Tester Instrument Calibration

The Sutherland Rub Tester must first be calibrated prior to use. First,turn on the Sutherland Rub Tester by moving the tester switch to the“cont” position. When the tester arm is in its position closest to theuser, turn the tester’s switch to the “auto” position. Set the tester torun 5 strokes by moving the pointer arm on the large dial to the “five”position setting. One stroke is a single and complete forward andreverse motion of the weight. The end of the rubbing block should be inthe position closest to the operator at the beginning and at the end ofeach test.

Prepare a tissue paper on cardboard sample as described above. Inaddition, prepare a felt on cardboard sample as described above. Both ofthese samples will be used for calibration of the instrument and willnot be used in the acquisition of data for the actual samples.

Place this calibration tissue sample on the base plate of the tester byslipping the holes in the board over the hold-down pins. The hold-downpins prevent the sample from moving during the test. Clip thecalibration felt/cardboard sample onto the four pound weight with thecardboard side contacting the pads of the weight. Make sure thecardboard/felt combination is resting flat against the weight. Hook thisweight onto the tester arm and gently place the tissue sample underneaththe weight/felt combination. The end of the weight closest to theoperator must be over the cardboard of the tissue sample and not thetissue sample itself. The felt must rest flat on the tissue sample andmust be in 100% contact with the tissue surface. Activate the tester bydepressing the “push” button.

Keep a count of the number of strokes and observe and make a mental noteof the starting and stopping position of the felt covered weight inrelationship to the sample. If the total number of strokes is five andif the end of the felt covered weight closest to the operator is overthe cardboard of the tissue sample at the beginning and end of thistest, the tester is calibrated and ready to use. If the total number ofstrokes is not five or if the end of the felt covered weight closest tothe operator is over the actual paper tissue sample either at thebeginning or end of the test, repeat this calibration procedure until 5strokes are counted the end of the felt covered weight closest to theoperator is situated over the cardboard at the both the start and end ofthe test.

During the actual testing of samples, monitor and observe the strokecount and the starting and stopping point of the felt covered weight.Recalibrate when necessary.

Lint Testing - Hunter Color Meter Calibration

Adjust the Hunter Color Difference Meter for the black and whitestandard plates according to the procedures outlined in the operationmanual of the instrument. Also run the stability check forstandardization as well as the daily color stability check if this hasnot been done during the past eight hours. In addition, the zeroreflectance must be checked and readjusted if necessary.

Place the white standard plate on the sample stage under the instrumentport. Release the sample stage and allow the sample plate to be raisedbeneath the sample port.

Using the “L-Y”,“a-X”, and “b-Z” standardizing knobs, adjust theinstrument to read the Standard White Plate Values of “L”, “a”, and “b”when the “L”, “a”, and “b” push buttons are depressed in turn.

Lint Testing - Measurement of Samples

The first step in the measurement of lint is to measure the Hunter colorvalues of the black felt/cardboard samples prior to being rubbed on thetissue. The first step in this measurement is to lower the standardwhite plate from under the instrument port of the Hunter colorinstrument. Center a felt covered cardboard, with the arrow pointing tothe back of the color meter, on top of the standard plate. Release thesample stage, allowing the felt covered cardboard to be raised under thesample port.

Since the felt width is only slightly larger than the viewing areadiameter, make sure the felt completely covers the viewing area. Afterconfirming complete coverage, depress the L push button and wait for thereading to stabilize. Read and record this L value to the nearest 0.1unit.

If a D25D2A head is in use, lower the felt covered cardboard and plate,rotate the felt covered cardboard 90 degrees so the arrow points to theright side of the meter. Next, release the sample stage and check oncemore to make sure the viewing area is completely covered with felt.Depress the L push button. Read and record this value to the nearest 0.1unit. For the D25D2M unit, the recorded value is the Hunter Color Lvalue. For the D25D2A head where a rotated sample reading is alsorecorded, the Hunter Color L value is the average of the two recordedvalues.

Measure the Hunter Color L values for all of the felt covered cardboardsusing this technique. If the Hunter Color L values are all within 0.3units of one another, take the average to obtain the initial L reading.If the Hunter Color L values are not within the 0.3 units, discard thosefelt/cardboard combinations outside the limit. Prepare new samples andrepeat the Hunter Color L measurement until all samples are within 0.3units of one another.

For the measurement of the actual tissue paper/cardboard combinations,place the tissue sample/cardboard combination on the base plate of thetester by slipping the holes in the board over the hold-down pins. Thehold-down pins prevent the sample from moving during the test. Clip thecalibration felt/cardboard sample onto the four pound weight with thecardboard side contacting the pads of the weight. Make sure thecardboard/felt combination is resting flat against the weight. Hook thisweight onto the tester arm and gently place the tissue sample underneaththe weight/felt combination. The end of the weight closest to theoperator must be over the cardboard of the tissue sample and not thetissue sample itself. The felt must rest flat on the tissue sample andmust be in 100% contact with the tissue surface.

Next, activate the tester by depressing the “push” button. At the end ofthe five strokes the tester will automatically stop. Note the stoppingposition of the felt covered weight in relation to the sample. If theend of the felt covered weight toward the operator is over cardboard,the tester is operating properly. If the end of the felt covered weighttoward the operator is over sample, disregard this measurement andrecalibrate as directed above in the Sutherland Rub Tester Calibrationsection.

Remove the weight with the felt covered cardboard. Inspect the tissuesample. If torn, discard the felt and tissue and start over. If thetissue sample is intact, remove the felt covered cardboard from theweight. Determine the Hunter Color L value on the felt covered cardboardas described above for the blank felts. Record the Hunter Color Lreadings for the felt after rubbing. Rub, measure, and record the HunterColor L values for all remaining samples.

After all tissues have been measured, remove and discard all felt. Feltsstrips are not used again. Cardboards are used until they are bent,torn, limp, or no longer have a smooth surface.

Lint Testing - Calculations

Determine the delta L values by subtracting the average initial Lreading found for the unused felts from each of the measured values forthe off-Yankee and Yankee sides of the sample. Recall, multi-ply-plyproduct will only rub one side of the paper. Thus, three delta L valueswill be obtained for the multi-ply product. Average the three delta Lvalues and subtract the felt factor from this final average. This finalresult is termed the lint for the fabric side of the 2-ply product.

For the single-ply product where both Yankee side and off-Yankee sidemeasurements are obtained, subtract the average initial L reading foundfor the unused felts from each of the three Yankee side L readings andeach of the three off-Yankee side L readings. Calculate the averagedelta for the three Yankee side values. Calculate the average delta forthe three fabric side values. Subtract the felt factor from each ofthese averages. The final results are termed a lint for the fabric sideand a lint for the Yankee side of the single-ply product. By taking theaverage of these two values, an ultimate lint value is obtained for theentire single-ply product.

Basis Weight

Using a dye and press, six 76.2 mm by 76.2 mm square samples were cutfrom a 2-ply product being careful to avoid any web perforations. Thesamples were placed in an oven at 105 deg C for 5 minutes before beingweighed on an analytical balance to the fourth decimal point. The weightof the sample in grams was divided by (0.0762 m) ² to determine thebasis weight in grams/m².

Caliper Testing

A Thwing-Albert ProGage 100 Thickness Tester, manufactured by ThwingAlbert of West Berlin, NJ was used for the caliper test. Eight 100 mm ×100 mm square samples were cut from a 2-ply product. The samples werethen tested individually and the results were averaged to obtain acaliper result for the base sheet.

The following two Examples illustrate the advantages of the presentinvention.

Example

2-ply laminate tissue with HF > 91.0 and lint value < 5.0

Two webs of through air dried tissue were laminated to produce a roll of2-ply sanitary (bath) tissue with 190 sheets each 4.0 inches long and4.0 inches wide. The laminate was rolled on a roll that was 121 mm indiameter. The 2-ply tissue had the following product attributes: a BasisWeight of 37.8 g/m², a Caliper of 0.517 mm, an MD tensile of 150 N/m, aCD tensile of 83 N/m, a ball burst of 195 grams force, a lint value of4.86, an MD stretch of 13.4%, a CD stretch of 6.4%, a CD wet tensile of9 N/m, a HF of 91.9 and a TS7 of 8.26.

Each tissue web was multilayered with the fiber and chemistry of eachlayer selected and prepared individually to maximize product qualityattributes of softness and strength. The first exterior layer, which wasthe layer that contacted the Yankee dryer, was prepared using 80%eucalyptus with 0.25 kg/ton of the amphoteric starch Redibond 2038 (CornProducts, 10 Finderne Avenue, Bridgewater, New Jersey 08807) (for lintcontrol) and 0.25 kg/ton of the glyoxylated polyacrylamide Hercobond1194 (Ashland, 500 Hercules Road, Wilmington DE, 19808) (for strengthwhen wet and for lint control). The remaining 20% of the first exteriorlayer was northern bleached softwood kraft fibers. The interior layerwas composed of 40% northern bleached softwood kraft fibers, 60%eucalyptus fibers, and 1.0 kg/ton of T526, a softener/debonder (EKAChemicals Inc., 1775 West Oak Commons Court, Marietta, GA, 30062). Thesecond exterior layer was composed of 20% northern bleached softwoodkraft fibers, 80% eucalyptus fibers and 3.0 kg/ton of Redibond 2038 (tolimit refining and impart Z-direction strength). The softwood fiberswere refined at 115 kwh/ton to impart the necessary tensile strength.

The fiber and chemicals mixtures were diluted to solids of 0.5%consistency and fed to separate fan pumps, which delivered the slurry toa triple layered headbox. The headbox pH was controlled to 7.0 byaddition of a caustic to the thick stock that was fed to the fan pumps.The headbox deposited the slurry to a nip formed by a forming roll, anouter forming wire, and inner forming wire. The slurry was drainedthrough the outer wire, of a KT194-P design by Asten Johnson (4399Corporate Rd, Charleston, SC USA), to aid with drainage, fiber support,and web formation. When the fabrics separated, the web followed theinner forming wire and dried to approximately 25% solids using a seriesof vacuum boxes and a steam box.

The web was then transferred to a structured fabric with the aid of avacuum box to facilitate fiber penetration into the structured fabric toenhance bulk softness and web imprinting. The structured fabric used wasa Prolux 005 design supplied by Albany (216 Airport Drive Rochester, NHUSA), which has a 5 shed design with a warp pick sequence of 1, 3, 5, 2,4, a 17.8 by 11.1 yarn/cm Mesh and Count, a 0.35 mm warp monofilament, a0.50 mm weft monofilament, a 1.02 mm caliper, a permeability value of640 cubic feet of air per minute (cfm), and a knuckle surface that wassanded to impart a 27% contact area with the Yankee dryer. The web wasdried with the aid of two TAD hot air impingement drums to 85% moisturebefore being transferred to the Yankee dryer.

The web was held in intimate contact with the Yankee drum surface usingan adhesive coating chemistry. The Yankee dryer was provided with steamat 3.0 bar while the installed hot air impingement hood over the Yankeedryer was blowing heated air at up to 450° C. In accordance with anexemplary embodiment of the present invention, the web was creped fromthe yankee dryer at 10% crepe (speed differential between the yankeedryer and reel drum) using a blade with a wear resistant chromia titaniamaterial with a set up angle of 20 degrees, a 0.50 mm creping shelfdistance, and an 80 degree blade bevel. In alternative embodiments, theweb may be creped from the Yankee at 10% crepe using a ceramic blade ata pocket angle of 90 degrees. The caliper of the web was approximately375 microns (single ply) before traveling through the calender to reducethe bulk to 275 microns (single ply). The web was cut into two of equalwidth using a high pressure water stream at 10,000 psi and was reeledinto two equally sized parent rolls and transported to the convertingprocess.

In the converting process, the two webs were plied together usingmechanical ply bonding, or light embossing of the DEKO configuration(only the top sheet is embossed with glue applied to the inside of thetop sheet at the high points derived from the embossments using andadhesive supplied by a cliché roll) with the second exterior layer ofeach web facing each other. The embossment coverage on the top sheet was4%. The product was wound into a 190 sheet count roll at 121 mm.

An alternative process was also performed in which the web was notcalendered on the paper machine before being converted as describedabove. In that case, the web was wound into a 176 count product at 121mm and had approximately the same physical properties as describedpreviously.

Comparative Example

2-ply laminate tissue with HF > 91.0 and lint value < 6.1

Two webs of through air dried tissue were laminated to produce a roll of2-ply sanitary (bath) tissue with 190 sheets each 4.0 inches long and4.0 inches wide. The laminate was rolled on a roll that was 121 mm indiameter. The 2-ply tissue further had the following product attributes:a Basis Weight of 38.2 g/m², a Caliper of 0.525 mm, an MD tensile of 155N/m, a CD tensile of 82 N/m, a ball burst of 222 grams force, a lintvalue of 6.04, an MD stretch of 11.9%, a CD stretch of 7.2%, a CD wettensile of 8.7 N/m, a HF of 92.2 and a TS7 of 8.5.

Each tissue web was multilayered with the fiber and chemistry of eachlayer selected and prepared individually to maximize product qualityattributes of softness and strength. The first exterior layer, whichcontacted the Yankee dryer, was prepared using 95% eucalyptus with 0.25kg/ton of the amphoteric starch Redibond 2038 (Corn Products, 10Finderne Avenue, Bridgewater, New Jersey 08807) (for lint control) and0.25 kg/ton of the glyoxylated polyacrylamide Hercobond 1194 (Ashland,500 Hercules Road, Wilmington DE, 19808) (for strength when wet and forlint control). The remaining 5% of the first exterior layer was northernbleached softwood kraft fibers. The interior layer was composed of 40%northern bleached softwood kraft fibers, 60% eucalyptus fibers, and 1.5kg/ton of T526, a softener/debonder from EKA Chemicals Inc., 1775 WestOak Commons Court, Marietta, GA USA. The second exterior layer wascomposed of 20% northern bleached softwood kraft fibers, 80% eucalyptusfibers and 3.0 kg/ton of Redibond 2038 (to limit refining and impartZ-direction strength). The softwood fibers were refined at 135 kwh/tonto impart the necessary tensile strength.

The fiber and chemicals mixtures were diluted to solids of 0.5%consistency and fed to separate fan pumps which delivered the slurry toa triple layered headbox. The headbox pH was controlled to 7.0 by theaddition of a caustic to the thick stock that was fed to the fan pumps.The headbox deposited the slurry to a nip formed by a forming roll, anouter forming wire, and inner forming wire. The slurry was drainedthrough the outer wire, which was a KT194-P design supplied by AstenJohnson (4399 Corporate Rd, Charleston, SC USA), to aid with drainage,fiber support, and web formation. When the fabrics were separated, theweb followed the inner forming wire and was dried to approximately 25%solids using a series of vacuum boxes and a steam box.

The web was then transferred to a structured fabric which the aid of avacuum box to facilitate fiber penetration into the structured fabric toenhance bulk softness and web imprinting. The structured fabric was aProlux 005 design supplied by Albany (216 Airport Drive Rochester, NHUSA) with a 5 shed design with a warp pick sequence of 1, 3, 5, 2, 4, a17.8 by 11.1 yarn/cm Mesh and Count, a 0.35 mm warp monofilament, a 0.50mm weft monofilament, a 1.02 mm caliper, with a 640 cfm and a knucklesurface that was sanded to impart 27% contact area with the Yankeedryer. The web was dried with the aid of two TAD hot air impingementdrums to 85% moisture before being transferred to the Yankee dryer.

The web was held in intimate contact with the Yankee dryer surface usingan adhesive coating chemistry. The Yankee dryer was provided with steamat 3.0 bar while the installed hot air impingement hood over the Yankeewas blowing heated air up to 450° C. In accordance with an exemplaryembodiment of the present invention, the web was creped from the yankeeat 10% crepe (speed differential between the yankee dryer and reel drum)using a blue steel material with a set up angle of 20 degrees, a 1.2 mmcreping shelf distance, and an 80 degree blade bevel. In alternativeembodiments, the web may be creped from the Yankee dryer at 10% crepeusing a ceramic blade at a pocket angle of 90 degrees. The caliper ofthe web was approximately 375 microns (single ply) before travelingthrough the calender to reduce the bulk to 275 microns (single ply). Theweb was cut into two webs of equal width using a high pressure waterstream at 10,000 psi and reeled into two equally sized parent rolls andtransported to the converting process.

In the converting process, the two webs were plied together usingmechanical ply bonding, or light embossing of the DEKO configuration(only the top sheet was embossed with glue applied to the inside of thetop sheet at the high points derived from the embossments using andadhesive supplied by a cliché roll) with the second exterior layer ofeach web facing each other. The embossment coverage on the top sheet was4%. The product was wound into a 190 sheet count product at 121 mm.

An alternative process was also performed in which the web was notcalendered on the paper machine before being converted as describedabove. In that case, the web was wound into a 176 count product at 121mm and had approximately the same physical properties as describedpreviously.

Comparative Test Results From Commercially Available Products

Table 1 shows comparative test results for similar testing performed onvarious commercially available products. The test results are shown forbasis weight, bulk, Dry MD and CD strength and stretch, Wet CD strength,Performance, Geometric Mean Tensile (GMT) strength, ball burst, HF andlint value.

The tests confirm that the present invention is advantageous as all ofthe other tested products do not demonstrate the same levels of highsoftness and low lint. For example, all of the commercially availableproducts demonstrated lower softness (i.e., lower HF values) compared tothe Example, and in some cases, higher lint values compared to theExample combined with the lower softness.

TABLE 1 Competitor Quality Attributes (6 samples tested and averaged foreach month when tested) g/m^(∧)2 microns N/m % N/m $ N/m N/m N/m gf HFBrand/location Date Month-Year Paper Type Basis Wt Bulk MD Strength MDStretch CD Strength CD Stretch CD Wet Perf. GMT Ball Burst Softness LintValue Charmin Strong/ Walmart Jan-15 TAD-2ply 35.73 516.78 168.34 18.2274.56 14.07 14.17 55.03 111.97 287.12 87.57 3.50 Charmin Strong/ WalmartFeb-15 TAD-2ply 37.03 555.25 190.57 16.70 85.13 11.99 12.79 73.04 127.34332.45 87.47 4.87 Charmin Strong/ Walmart Mar-15 TAD-2ply 37.34 487.12183.47 16.99 85.60 13.86 18.62 67.80 125.30 322.85 89.45 6.77 CharminStrong/ Walmart Apr-15 TAD-2ply 37.49 578.33 210.23 18.70 100.51 9.7715.89 64.01 145.23 334.47 86.55 5.20 Charmin Strong/ Walmart May-15TAD-2ply 37.38 570.92 169.43 16.30 83.60 12.00 17.45 62.86 118.90 343.4088.02 3.79 Charmin Strong/ Walmart Jun-15 TAD-2ply 43.14 537.50 235.0618.23 131.21 9.65 20.77 81.27 175.51 358.40 87.98 5.75 Charmin Strong /Sam’s Club Jan-15 TAD-2ply 36.58 553.53 178.49 17.56 70.23 13.02 15.0273.17 111.76 296.56 91.53 7.31 Charmin Strong / Sam’s Club Feb-15TAD-2ply 36.42 406.33 228.86 19.25 101.71 10.80 22.79 71.83 152.27353.18 89.57 3.79 Charmin Strong / Sam’s Club Mar-15 TAD-2ply 37.00469.13 161.23 17.09 81.78 12.30 17.17 58.00 114.73 289.48 91.03 NotTested Charmin Strong / Sam’s Club Apr-15 TAD-2ply 37.69 458.62 174.6217.11 87.32 8.83 17.47 57.73 123.38 334.14 89.80 6.32 Charmin Strong /Sam’s Club May-15 TAD-2ply 37.75 461.93 183.25 17.16 96.38 11.20 19.0965.53 132.88 369.52 87.32 3.33 Charmin Strong / Sam’s Club Jun-15TAD-2ply 37.58 450.10 180.81 16.27 89.64 11.68 17.53 73.84 127.12 357.7390.95 5.51 Charmin Soft -/Walmart Jan-15 TAD-2ply 45.60 602.92 111.1022.98 55.45 9.21 15.92 53.27 78.41 196.47 97.63 13.08 Charmin Soft-/Walmart Feb-15 TAD-2ply 45.37 648.58 133.00 25.77 59.48 10.45 12.9061.92 88.88 207.76 95.80 7.26 Charmin Soft -/Walmart Mar-15 TAD-2ply45.29 491.48 107.69 22.34 56.80 12.11 11.90 69.91 78.17 211.64 96.808.64 Charmin Soft -/Walmart Apr-15 TAD-2ply 47.35 658.47 127.66 26.1058.57 9.50 13.18 78.13 86.42 246.18 97.63 8.87 Charmin Soft -/WalmartMay-15 TAD-2ply 46.96 610.87 147.44 23.45 64.40 9.87 17.39 74.92 97.08245.50 97.05 10.35 Charmin Soft -/Walmart Jun-15 TAD-2ply 47.23 594.97134.01 22.78 61.16 12.96 14.85 68.11 90.49 265.72 97.57 8.28 CharminSoft /Sam’s Club Jan-15 TAD-2ply 47.06 576.18 122.53 23.55 56.12 11.0214.21 54.09 82.74 224.11 95.12 6.81 Charmin Soft /Sam’s Club Feb-15TAD-2ply 47.91 554.00 108.79 23.61 55.29 10.14 14.93 47.13 77.48 211.8098.70 9.39 Charmin Soft /Sam’s Club Mar-15 TAD-2ply 47.27 566.18 105.1322.59 50.24 10.17 14.51 48.82 72.54 189.56 97.05 9.65 Charmin Soft/Sam’s Club Apr-15 TAD-2ply 47.87 578.66 113.97 20.50 53.36 9.36 15.0661.61 77.84 225.96 97.57 8.31 Charmin Soft /Sam’s Club May-15 TAD-2ply47.14 539.53 145.64 26.07 63.59 9.04 16.55 70.95 96.23 237.42 95.22 7.60Charmin Soft /Sam’s Club Jun-15 TAD-2ply 48.03 537.13 141.38 23.33 62.0211.04 14.36 147.66 93.62 242.64 97.13 8.29 White Cloud 2ply/WalmartMay-15 TAD-2ply 42.47 444.13 194.54 16.80 117.25 6.18 19.79 83.80 150.84253.76 87.63 5.42 White Cloud 2ply/Walmart Jun-15 TAD-2ply 39.31 506.22185.72 20.58 105.59 6.76 11.00 77.60 140.01 238.76 88.15 6.34 KirklandSignature /Costco Jan-15 Conventional 2-ply 37.16 293.37 168.80 25.3355.45 8.85 10.68 56.66 96.68 209.78 86.12 5.43 Kirkland Signature/Costco Feb-15 Conventional 2-ply 37.75 310.67 117.91 24.90 47.71 7.207.03 46.10 74.88 117.28 84.95 1.46 Kirkland Signature /Costco Mar-15Conventional 2-ply 35.75 405.05 140.05 22.13 47.97 7.44 8.12 47.19 81.85138.34 82.62 2.43 Kirkland Signature /Costco Apr-15 Conventional 2-ply35.67 309.47 135.52 24.77 45.52 6.72 7.98 49.97 78.39 131.60 88.63 5.48Kirkland Signature /Costco May-15 Conventional 2-ply 36.94 366.40 138.2423.62 46.60 5.05 9.33 57.62 80.18 105.48 87.78 2.23 Kirkland Signature/Costco Jun-15 Conventional 2-ply 37.20 319.10 129.33 24.53 49.41 7.147.77 56.62 79.82 132.44 87.28 3.85 Great Value Ultra Soft/Walmart Mar-15TAD-2 ply 47.63 554.63 131.06 13.61 100.55 6.13 10.90 48.41 114.69204.05 85.68 6.20 Great Value Ultra Soft/Walmart Apr-15 TAD-2-ply 48.12505.03 167.81 13.78 80.72 5.33 12.16 62.45 116.20 206.80 88.17 9.09Great Value Ultra Soft/Walmart Jun-15 TAD-2ply 47.91 500.25 189.98 21.08120.51 5.92 13.05 64.24 151.29 234.05 72.18 7.38 Up&Up / Target Jan-15TAD-2 ply 39.92 530.77 152.61 14.36 53.16 7.29 12.15 62.72 89.87 178.7888.38 6.76 Up&Up / Target Feb-15 TAD-2ply 43.28 544.13 157.74 11.4968.48 5.99 12.14 63.60 103.88 207.59 90.38 8.64 Up&Up / Target Mar-15TAD-2ply 39.16 544.48 147.43 13.07 70.35 6.83 9.96 68.50 101.52 214.8490.48 6.20 Up&Up / Target Apr-15 TAD-2ply 38.97 525.13 195.83 13.6382.88 6.62 10.64 81.33 127.31 250.73 86.12 5.62 Up&Up / Target May-15TAD-2ply 38.44 527.37 172.95 13.38 88.27 6.37 11.30 89.42 123.48 237.0884.90 5.60 Up&Up / Target Jun-15 TAD-2ply 42.88 544.97 161.72 11.2769.03 6.52 12.44 66.81 105.64 194.62 90.47 9.27 Charmin Sensitive/Walmart Jan-15 TAD-2ply 42.17 540.13 124.91 18.40 75.62 8.78 9.68 56.2597.10 265.05 87.57 4.11 Charmin Sensitive/ Walmart Mar-15 TAD-2 ply42.45 643.00 116.52 21.88 76.18 11.19 12.69 57.04 94.12 215.51 86.772.74 Home Ultra Soft/ Safeway Jan-15 TAD 2ply 48.66 540.03 202.50 18.40105.20 6.36 10.91 55.78 145.77 182.15 86.88 7.77 Home Ultra Soft/Safeway Feb-15 TAD 2ply 50.24 555.82 168.09 22.63 110.62 6.54 14.4776.81 136.16 248.71 87.40 4.86 Home Ultra Soft/ Safeway Apr-15 TAD 2ply49.29 547.42 191.75 22.68 123.89 5.20 14.46 61.15 154.13 233.20 86.255.21 Home Ultra Soft/ Safeway Jun-15 TAD 2ply 48.70 525.23 194.68 19.35104.07 7.20 10.20 85.06 142.34 241.80 85.80 6.96 Scott Extra Soft/Walmart Jun-15 UCTAD 1 ply 28.24 502.57 122.05 9.70 51.79 11.55 6.9676.41 79.44 199.84 81.70 2.96 Scott-1000/ Walmart Jun-15 Conventional1ply 16.86 143.42 155.01 16.40 63.79 6.88 2.36 88.16 99.20 132.95 67.020.33 Cottonelle/ Walmart Jan-15 UCTAD 1ply 39.30 714.42 107.06 15.3163.11 10.35 13.23 67.05 82.10 163.95 84.18 5.80 Cottonelle/ WalmartFeb-15 UCTAD 1ply 40.92 627.43 130.55 18.54 55.79 9.65 11.44 72.80 85.21118.62 87.17 7.89 Cottonelle/ Walmart Mar-15 UCTAD 1ply 38.10 634.77155.52 16.87 74.20 13.17 11.42 88.03 107.20 213.83 83.60 5.21Cottonelle/ Walmart Apr-15 UCTAD 1ply 40.35 651.78 134.39 15.44 70.479.42 13.40 82.72 97.19 193.78 82.48 6.36 Angel Soft/ Walmart Jan-15Conventional 2ply 37.28 413.88 181.34 25.57 65.07 9.50 10.52 62.63108.53 234.55 78.73 2.05 Angel Soft/ Walmart Feb-15 Conventional 2ply36.97 540.30 163.81 19.11 54.96 8.66 7.98 63.92 94.74 209.78 76.65 2.86Angel Soft/ Walmart Mar-15 Conventional 2ply 36.46 494.80 124.45 19.7449.64 9.58 4.68 60.13 78.34 203.55 79.82 2.14 Angel Soft/ Walmart Apr-15Conventional 2ply 37.50 435.60 169.47 19.72 59.39 7.62 7.05 62.88 100.19220.57 83.08 4.34 Cottonelle Ultra/ Walmart Feb-15 UCTAD 2ply 44.44747.23 184.03 10.66 78.93 11.41 12.27 111.24 120.47 338.18 84.95 6.96Cottonelle Ultra/ Walmart Apr-15 UCTAD 2 ply 44.62 733.88 169.15 11.1473.78 9.84 12.63 110.42 111.34 287.80 84.07 5.36 Cottonelle Ultra/Walmart Jun-15 UCTAD 2 ply 42.16 536.37 150.98 10.85 64.49 10.66 9.2098.03 98.61 252.92 86.17 6.29

Now that embodiments of the present invention have been shown anddescribed in detail, various modifications and improvements thereon willbecome readily apparent to those skilled in the art. Accordingly, thespirit and scope of the present invention is to be construed broadly andnot limited by the foregoing specification.

What is claimed is:
 1. A roll bath tissue comprising: a laminate of atleast two plies of a multi-layer through air dried tissue, each plycomprising a first exterior layer, an interior layer and a secondexterior layer, the roll bath tissue having a bulk softness of less than10 TS7, a lint value of 5.0 or less, an Average Peak to Valley Wavinessof 140 microns or less, a waviness uniformity of 27 microns or less, anda caliper greater than 510 microns/2 ply, wherein the first and secondexterior layers are substantially free of any surface-deposited softeneragents or lotions.
 2. The roll bath tissue of claim 1, wherein the firstexterior layer comprises a wet end dry strength additive.
 3. The rollbath tissue of claim 1, wherein the interior layer is comprised of atleast 75% by weight of softwood fibers.
 4. The roll bath tissue of claim1, wherein the second exterior layer further comprises a wet end drystrength additive.
 5. The roll bath tissue of claim 1, wherein thesecond exterior layer further comprises a temporary wet strengthadditive.
 6. The roll bath tissue of claim 1, wherein the secondexterior layer further comprises a dry strength additive.
 7. The rollbath tissue of claim 1, wherein the first exterior layer furthercomprises a dry strength additive.
 8. The roll bath tissue of claim 1,having an MD tensile strength and a CD tensile strength of at least 35N/m and having a basis weight of less than 40 gsm.
 9. The roll bathtissue of claim 1, having an MD tensile strength and a CD tensilestrength of at least 35 N/m and a caliper of less than 650 microns. 10.The roll bath tissue of claim 1, wherein the tissue further comprises anon-ionic surfactant having a hydrophilic-lipophilic balance of lessthan
 10. 11. The roll bath tissue of claim 1, wherein each of the atleast two plies comprises an embossed area, wherein the embossed areaoccupies between approximately 3 to 15% of the total surface area of asurface of the ply.
 12. The roll bath tissue of claim 1, wherein thetissue has an Average Primary Amplitude of 50 microns or less and anAmplitude Uniformity of 8 microns or less.
 13. A roll bath tissuecomprising: a laminate of at least two plies of a multi-layer throughair dried tissue, each ply comprising a first exterior layer, aninterior layer and a second exterior layer, the roll bath tissue havinga bulk softness of 8.2 to 10 TS7, a lint value of 5.0 or less, anAverage Peak to Valley Waviness of 140 microns or less, and an AveragePrimary Amplitude of 50 microns or less, wherein the first and secondexterior layers are substantially free of any surface-deposited softeneragents or lotions.
 14. The roll bath tissue of claim 13, wherein thefirst exterior layer comprises a wet end dry strength additive.
 15. Theroll bath tissue of claim 13, wherein the interior layer is comprised ofat least 75% by weight of softwood fibers.
 16. The roll bath tissue ofclaim 13, wherein the second exterior layer further comprises a wet enddry strength additive.
 17. The roll bath tissue of claim 13, wherein thesecond exterior layer further comprises a temporary wet strengthadditive.
 18. The roll bath tissue of claim 13, wherein the secondexterior layer further comprises a dry strength additive.
 19. The rollbath tissue of claim 13, wherein the first exterior layer furthercomprises a dry strength additive.
 20. The roll bath tissue of claim 13,having an MD tensile strength and a CD tensile strength of at least 35N/m and having a basis weight of less than 40 gsm.
 21. The roll bathtissue of claim 13, having an MD tensile strength and a CD tensilestrength of at least 35 N/m and a caliper of less than 650 microns. 22.The roll bath tissue of claim 13, wherein the tissue further comprises anon-ionic surfactant having a hydrophilic-lipophilic balance of lessthan
 10. 23. The roll bath tissue of claim 13, wherein each of the atleast two plies comprises an embossed area, wherein the embossed areaoccupies between approximately 3 to 15% of the total surface area of asurface of the ply.
 24. The roll bath tissue of claim 13, wherein thetissue has an Amplitude Uniformity of 8 microns or less.
 25. A roll bathtissue comprising: a laminate of at least two plies of a multi-layerthrough air dried tissue, each ply comprising a first exterior layer, aninterior layer and a second exterior layer, the roll bath tissue havinga softness of greater than 90 HF, a lint value of 5.0 or less, anAverage Peak to Valley Waviness of 140 microns or less, and an AveragePrimary Amplitude of 50 microns or less, wherein the first and secondexterior layers are substantially free of any surface-deposited softeneragents or lotions.
 26. The roll bath tissue of claim 25, wherein thefirst exterior layer comprises a wet end dry strength additive.
 27. Theroll bath tissue of claim 25, wherein the interior layer is comprised ofat least 75% by weight of softwood fibers.
 28. The roll bath tissue ofclaim 25, wherein the second exterior layer further comprises a wet enddry strength additive.
 29. The roll bath tissue of claim 25, wherein thesecond exterior layer further comprises a temporary wet strengthadditive.
 30. The roll bath tissue of claim 25, wherein the secondexterior layer further comprises a dry strength additive.
 31. The rollbath tissue of claim 25, wherein the first exterior layer furthercomprises a dry strength additive.
 32. The roll bath tissue of claim 25,having an MD tensile strength and a CD tensile strength of at least 35N/m and having a basis weight of less than 40 gsm.
 33. The roll bathtissue of claim 25, having an MD tensile strength and a CD tensilestrength of at least 35 N/m and a caliper of less than 650 microns. 34.The roll bath tissue of claim 25, wherein the tissue further comprises anon-ionic surfactant having a hydrophilic-lipophilic balance of lessthan
 10. 35. The roll bath tissue of claim 25, wherein each of the atleast two plies comprises an embossed area, wherein the embossed areaoccupies between approximately 3 to 15% of the total surface area of asurface of the ply.
 36. The roll bath tissue of claim 25, wherein thetissue has an Amplitude Uniformity of 8 microns or less.